Method of forming an electrical connector

ABSTRACT

An electrical connector for a composite core conductor and a method of controlling crimping thereof includes a coupling portion and a tubular portion extending from the coupling portion. A conductor has a non-metallic core surrounded by electrically conductive strands and has a connecting portion of the core extending axially beyond the strands. The connecting portion is received in the tubular portion. A crimped portion on the tubular portion radially engages the connecting portion and secures the conductor to the tubular portion. The crimped portion is formed by concave surfaces on internal surfaces of crimping dies. The concave surfaces have different radii of curvature than remaining portions of the internal surfaces.

CROSS REFERENCE TO RELATED APPLICATION

This application is divisional application of Ser. No. 14/052,197 filedOct. 11, 2013 which claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application Ser. No. 61/800,255, filed Mar. 15, 2013, whichis hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to electrically connecting acomposite core conductor. More particularly, the present inventionrelates to a crimp die for connecting a composite core of a conductor toan electrical connector. Still more particularly, the present inventionrelates to a method of connecting a composite core of a conductor to anelectrical connector.

BACKGROUND OF THE INVENTION

The vast majority of high voltage transmission conductors used includesstrands of high strength steel surrounded by multiple strands ofaluminum wire. The steel strands are the principle load bearingcomponent holding up the wire, while the softer, more elastic aluminumstrands include the majority of the electrical power transportcomponent. Many variations of transmission wire operating at betweenapproximately 115 kv to 800 kV involve this basic design concept andhave these two basic components.

More recently, a composite core conductor having a fiberglass and epoxyresin core covered by aluminum wire has emerged as a substitute for thesteel support stranding in high voltage transmission conductors.However, the outer surface of the composite core is difficult tomechanically connect to a compression tube of a connector member. Theouter surface of the composite core is sensitive, such that a scratch onthe outer surface can lead to a fracture of the composite core. Due tothe sensitivity of the composite core, composite core conductors are notcrimped and are usually connected with wedge connectors such as isdisclosed in U.S. Pat. No. 7,858,882 to De France, which is herebyincorporated by reference in its entirety. Accordingly, a need existsfor an electrical connector in which a composite core conductor iscrimped thereto without damaging the outer surface of the compositecore.

A conventional crimp die 2 is shown in FIGS. 1-3. A plurality of planarsurfaces 3 form a crimp surface of the die 2. For example, the crimpsurface of each conventional die 2 is comprised of three planar surfaces3, as shown in FIG. 3. The planar surfaces 3 form a substantiallyhexagonal crimping area during the crimping process and result in a gap4 between the dies 2 and a tubular portion 5 in which the composite core26 is disposed, as shown in FIG. 2. The resulting gap 4 candetrimentally affect the outer surface of the composite core 26 as thecrimp is not completely controlled. Additionally, the planar surfaces 3provide a smaller area of compression 65 between the planar crimpsurfaces 3 and the outer surface of the tubular portion 5 in which thecomposite core 26 is disposed. Furthermore, the planar surfaces 3 of thecrimp die 2 apply compressive forces on tubular portion 5 at angles of31 degrees from a horizontal axis 6 through a center of the core 26 andvertically at 90 degrees from the horizontal axis 6, as shown in FIG. 1.Three areas of compression are formed with each die 2. Accordingly, aneed exists for a crimp die providing better crimp control of acomposite core conductor.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved electricalconnector in which a composite core of a composite core conductor iscrimped to the electrical connector.

Another object of the present invention is to provide an improvedelectrical connector member in which a composite core conductor is moreeasily and inexpensively crimped to an electrical connector.

Another object of the present invention is to provide an improvedcrimping die that crimps the composite core to an electrical connectorwithout damaging an outer surface of the composite core.

Another object of the present invention is to provide an improvedcrimping die proving improved crimp control when crimping a compositecore conductor.

The foregoing objectives are basically attained by an electricalconnector including a coupling portion and a tubular portion extendingfrom the coupling portion. A conductor has a non-metallic coresurrounded by electrically conductive strands and has a connectingportion of the core extending axially beyond the strands. The connectingportion is received in the tubular portion. A crimped portion on thetubular portion radially engages the connecting portion and secures theconductor to the tubular portion. The crimped portion is formed byconcave surfaces on internal surfaces of crimping dies. The concavesurfaces have different radii of curvature than remaining portions ofthe internal surfaces

The foregoing objectives are also basically attained by a method ofcrimping a conductor. A portion of electrically conductive strandssurrounding a non-metallic core of the conductor is removed from thecore. The exposed core of the conductor is inserted in a substantiallytubular portion extending from a coupling portion of an electricalconnector. The substantially tubular portion is crimped to the core toform a first crimped portion. The first crimped portion is formed byconcave surfaces on internal surfaces of crimping dies. The concavesurfaces have different radii of curvature than remaining portions ofthe internal surfaces.

Objects, advantages, and salient features of the invention will becomeapparent from the following detailed description, which, taken inconjunction with the annexed drawings, discloses an exemplary embodimentof the present invention.

As used in this application, the terms “front,” “rear,” “upper,”“lower,” “upwardly,” “downwardly,” and other orientational descriptorsare intended to facilitate the description of the exemplary embodimentsof the present invention, and are not intended to limit the structurethereof to any particular position or orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

The above benefits and other advantages of the various embodiments ofthe present invention will be more apparent from the following detaileddescription of exemplary embodiments of the present invention and fromthe accompanying drawing figures, in which:

FIG. 1 is an end elevational view of a conventional die crimping acomposite core of a composite core conductor;

FIG. 2 is an end elevational view of the conventional die of FIG. 1showing a gap between the dies prior to crimping;

FIG. 3 is an end elevational view of a conventional die for crimping acomposite core;

FIG. 4 is an end elevational view of a die crimping a composite core ofa composite core conductor in accordance with an exemplary embodiment ofthe present invention;

FIG. 5 is an end elevational view of the die of FIG. 4 prior tocrimping;

FIG. 6 is a perspective view of a die of FIG. 4;

FIG. 7 is a side elevational view of the die of FIG. 6;

FIG. 8 is an end elevational view of the die of FIG. 7;

FIG. 9 is an end elevational view of the die of FIG. 4 showing a contactarea of the die;

FIG. 10 is an enlarged end elevational view of the contact area of FIG.9;

FIG. 11 is an end elevational view of the die of FIG. 4 with a compositecore disposed therein;

FIG. 12 is a side elevational view in partial cross-section of anassembled electrical connector in accordance with an exemplaryembodiment of the present invention;

FIG. 13 is an exploded side elevational view of the electrical connectorof FIG. 12 prior to assembly;

FIG. 14 is a side elevational view of a composite core conductor;

FIG. 15 is an end elevational view of the composite core conductor ofFIG. 14;

FIG. 16 is a side elevational view partially in section of an eyebolt ofthe electrical connector of FIG. 12;

FIG. 17 is an end view of the eyebolt of FIG. 16; and

FIG. 18 is a side elevational view in cross-section of an outer sleeveof the electrical connector of FIG. 12;

Throughout the drawings, like reference numerals will be understood torefer to like parts, components and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The present invention generally relates to an electrical connector 21for receiving a composite core conductor 23, as shown in FIG. 12, and acrimp die 25, as shown in FIGS. 4-11, for crimping a composite core 26of the composite core conductor 23 to the electrical connector 21. Theelectrical connector 21 reduces the number of components used inexisting electrical connector assemblies, thereby reducing inventory andcosts. The crimp dies 25 and 46 of the crimp die set 47 substantiallyprevent damage to an outer surface 41 of the composite core 26 duringthe crimping process.

The composite core conductor 23, as shown in FIGS. 14 and 15, includes acomposite core 26 covered by a plurality of aluminum conductors 27. Thecomposite core 23 is preferably made of a combination of fiber glass andepoxy resin. The plurality of aluminum conductors 27 are wrapped aroundthe composite core 26. The composite core 26 reduces the weight of thecomposite core conductor 23 compared to traditional steel coreconductors, such that more aluminum conductors can be used, therebyincreasing electrical power capacity without increasing the outerdiameter of the conductor. Additionally, the more lightweight compositecore conductors 23 reduce sag associated with traditional steel coreconductors.

The electrical connector 21 includes an eyebolt 28 having asubstantially tubular portion 29 having an open first end 30 and aneyelet 31 connected to a second end 32, as shown in FIGS. 12, 16 and 17.An opening 44 in the eyelet 31 allows the electrical connector 21 to beconnected to a support, such as a transmission tower. A ridge section 33is disposed on an outer surface 42 of the tubular portion 29 between thefirst and second ends 30 and 32. A cavity 34 having an inner surface 35extends inwardly from the first end 30 of the eyebolt 28. Preferably,the eyebolt 28 is unitarily formed as a single piece and is made ofmetal, such as steel or aluminum.

The tolerances of the tubular portion 29 are preferably extremely tightto more precisely control the inner and outer diameters thereof. Theinner diameter preferably has a tolerance of 0.001 inches. The outerdiameter preferably has a tolerance of 0.002 inches. By more preciselycontrolling the inner and outer diameters of the tubular portion 29,better control of the crimp between the tubular portion 29 and the core26 of the composite core conductor 23 is achieved, thereby substantiallypreventing damage to the composite core during crimping.

An outer sleeve 36 is substantially tubular and has an outer surface 45and first and second ends 37 and 38, as shown in FIGS. 12 and 18. Apassageway 39 having an inner surface 40 extends from the first end 37of the outer sleeve 36 to the second end 38, as shown in FIG. 18.Preferably, the diameter of the passageway 39 is substantially constant.Preferably, the outer sleeve 36 is unitarily formed as a single pieceand is made of an electrically conductive metal, such as aluminum.

A crimp die 25 in accordance with an exemplary embodiment of the presentinvention is shown in FIGS. 6-11. First and second dies 25 and 46 form adie set 47 to crimp composite core conductors 23. Preferably, the firstand second dies 25 and 46 are substantially identical.

The crimp die 25 has a crimping area 7 including first and secondcrimping surfaces 8 and 9 and a non-crimping surface 10, as shown inFIGS. 6-11. The crimping area 7 extends between first and secondsubstantially planar contact surfaces 48 and 49, as shown in FIGS. 6 and8. An outer side surface 50 of the die 25 is adapted to be received by acrimping tool (not shown) and extends externally between the first andsecond substantially planar contact surfaces 48 and 49. Substantiallyplanar front and rear surfaces 51 and 52 extend between the first andsecond planar contact surfaces 48 and 49 and are bounded by the outerside surface 50. Front and rear shoulders 53 and 54 are formed in thefront and rear surfaces 51 and 52, as shown in FIGS. 6 and 8. Beveledsurfaces 63 and 64 extend along upper edges of the front and rearsurfaces 51 and 52 to accommodate flashing or protrusions during thecrimping process.

The non-crimping surface 10 is disposed between the first and secondcrimping surfaces 8 and 9. The crimping surfaces 8 and 9 are concave.Center points 55 and 56 of the radii of the first and second crimpingsurfaces 8 and 9 are spaced from a center point 57 of the radius of thenon-crimping surface 10, as shown in FIG. 10, such that the crimpingsurfaces 8 and 9 have a different radius than the radius of thenon-crimping surface 10. Accordingly, the crimping surfaces 8 and 9 havea different radius of curvature than the non-crimping surface 10.Preferably, the radii of the first and second crimping surfaces 8 and 9are longer than the radius of the non-crimping surface 10. As anexample, the radius of the first and second crimping surfaces 8 and 9 is0.36 inches and the radius of the non-crimping surface 10 is 0.25inches.

Preferably, the two concave crimping surfaces 8 and 9 are approximately90 degrees apart on the crimping surface 7, as shown in FIG. 4. As shownin FIGS. 9-11, the concave crimping surfaces 8 increase the contact area43 between the crimping surface 7 and the tubular portion 29. The crimpsare applied approximately 180 degrees apart on the outer surface of thetubular portion 29 between diametrically opposite concave crimpingsurfaces 8 and 9 of opposing dies 25.

To assemble the electrical connector 21, a portion of the aluminumconductors 27 are removed from the conductor 23 to expose only thecomposite core 26, as shown in FIGS. 13 and 14. The exposed compositecore 26 is inserted in the cavity 34 of the tubular portion 29 of theeyebolt 28, as shown in FIG. 12. The tubular portion 29 and thecomposite core 26 are then crimped together in a crimping area 13, asshown in FIG. 12.

The dies 25 and 46 of FIGS. 6-11 are used to crimp the tubular portion29 to the composite core 26 to create a solid crimp connection withoutdamaging the outer surface of the composite core 26. The crimp toolapplies forces vertically on the crimp dies 25 and 46 as indicated byarrows 58 and 59 in FIG. 11. The crimping surfaces 8 and 9 are formedhaving two different radii such that the angle of compression isapproximately 45 degrees, as shown in FIG. 4. Accordingly, applyingforces 58 and 59 obliquely to the dies 25 and 46 results in crimpingforces being applied at 45 degree angles due to the crimping surfaces 8and 9 having a different radius than the non-crimping surface 10. Asshown in FIG. 5, crimping forces are diametrically opposed such that thecrimping forces are applied approximately 180 degrees apart. The concavecrimping surfaces 8 and 9 having two different radii portions increasesthe contact area between the crimping surfaces 8 and 9 and the tubularportion 29 of the eyebolt 28, as shown in FIG. 11. Additionally, thecompression dies 25 and 26 apply crimping forces that are diametricallyopposed (approximately 180 degrees apart) relative to a longitudinalaxis 6 of the composite core such that the composite core 26 iscompressed to a substantially circular shape, as shown in FIGS. 4 and 5.The compression dies 25 also have very close tolerances. The appliedcompression forces in the conventional dies, shown in FIGS. 1 and 2,result in the core 26 being compressed to an oval shape that coulddetrimentally affect performance of the conductor.

Additionally, the tubular portion 29 has very close tolerances on theinner diameter and outer diameter thereof such that a proper amount oftravel (or force) is applied during crimping. As shown in FIG. 4, closetolerances allow the contact surfaces 48 and 49 to engage during thecrimping process, thereby ensuring a proper crimp is obtained. As shownin FIG. 1, a gap 4 remains between the opposing dies 2 during thecrimping process such that the crimp is not accurately controlled duringthe crimping process, thereby resulting in under- and over-crimping. Thecrimp dies 25 and 46 substantially prevent over crimping that can damagethe composite core 26 and substantially prevent under crimping that canhave a detrimental effect on performance. Accordingly, a better crimpcan be obtained that does not substantially damage the outer surface ofthe composite core 26.

As shown in FIGS. 6 and 8, the crimping surfaces 8 and 9 of the crimpdies 25 and 46 are concave compared to the planar surfaces 3 of theconventional crimp dies 2 shown in FIGS. 1-3. The crimping surface ofthe conventional dies 2 is comprised of three planar surfaces 3, asshown in FIG. 3. The planar surfaces 3 result in a gap 4 between thecrimp dies 2, as shown in FIG. 1. As shown in FIG. 3, there is no gapbetween the crimp dies 25 and 46 during the crimp process when the crimpdies 25 and 46 have fully traveled. Additionally, the planar surfaces 3provide a smaller area of compression between the surfaces 3 and thecomposite core 26 and a smaller angle of compression (approximately 31degrees, as shown in FIG. 1).

The concave crimping surfaces 8 and 9 in accordance with exemplaryembodiments of the present invention as shown in FIGS. 6-11, provide alarger area of compression 60, as shown in FIG. 11, and a larger angleof compression (approximately 45 degrees). The dies 25 and 46 alsoincrease the angle of compression to approximately 45 degrees from the31 degree angle of compression shown in FIG. 1 for the conventionalcrimp dies 2.

The applied crimping forces 61 are diametrically opposed such that, incombination with the mating contact surfaces 48 and 49 substantiallyeliminating a gap between the dies 25 and 46 during the crimpingprocess, that the composite core 26 is compressed to a substantiallyrounded shape. Accordingly, the crimp dies 25 and 46 substantiallyprevent crimps that damage or otherwise detrimentally affect thecomposite core 26. Accordingly, a better crimp can be obtained that doesnot substantially damage the outer surface of the composite core 26.

The crimping surfaces 8 and 9 provide a non-damaging indent on the innersurface 35 of the tubular portion 29 of the eyebolt, as shown in FIG.16. A plurality of the crimps are performed on the outer surface 42 ofthe tubular portion 29 in a composite core crimping area (first crimpingarea) 13, which extends for substantially the length of the cavity 34 inthe tubular portion 29, as shown in FIG. 12. When the composite core 26has been crimped to the tubular portion 29, the outer sleeve 36 isdisposed over the tubular portion 29, as shown in FIG. 12. A first endof the outer sleeve 36 abuts a flange 62 of the eyebolt 28 and a secondend of the outer sleeve extends beyond the open end of the tubularportion 29 of the eyebolt 28.

The outer sleeve 36 is then crimped in second and third crimping areas11 and 12, as shown in FIG. 12, thereby securing the conductor 23 to theelectrical connector 21. The outer sleeve 36 is crimped to the eyebolt28 in the second crimping area 11. The outer sleeve 36 is crimped to theconductor 23 in the third crimping area 12. Any suitable crimping diescan be used for the crimping process in the second and third crimpingareas 11 and 12. The outer sleeve 36 is not crimped in the firstcrimping area 13 in which the tubular portion 29 of the eyebolt 28 iscrimped to the composite core 26. The eye bolt 28 can be anchored to anytype of structure. The structure may include, but is not limited to, apole, a building, a tower, or a substation.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the scope of the present invention. Thedescription of the exemplary embodiments of the present invention isintended to be illustrative, and not to limit the scope of the presentinvention. Various modifications, alternatives and variations will beapparent to those of ordinary skill in the art, and are intended to fallwithin the scope of the invention as defined in the appended claims andtheir equivalents.

What is claimed is:
 1. A method of forming an electrical connectorcomprising the steps of: inserting a non-metallic core of an electricalconductor into a substantially tubular portion of an electricalconnector; and crimping said tubular portion by a die Set including afirst crimping die and a second opposing crimping die to form aplurality of crimped portions on said tubular portion and non-crimpedportions, where each crimped portion on said tubular portion has aconcave configuration relative to said non-crimped portion of saidtubular portion and a convex surface area, said first crimping die andsaid second crimping die having a crimping area with a first concavecrimping surface, a second concave crimping surface, and a non-crimpingarea between said first crimping surface and second crimping surface,wherein said crimping step forms said tubular portion with asubstantially circular cross section on said non-metallic core.
 2. Themethod of claim 1, wherein said non-crimping area of said first crimpingdie and said second crimping die has a concave non-crimping surface, andwherein said crimping area extends between substantially planar contactsurfaces of said first crimping die and said second crimping die.
 3. Themethod of claim 2, wherein said first and second concave crimpingsurfaces of said crimping dies have a radius of curvature greater than aradius of curvature of said concave non-crimping surface, said crimpingsurfaces forming said crimped portions with a radius of curvaturegreater than a non-crimped portion of said tubular portion.
 4. Themethod of claim 1, wherein said first crimping surface of said first dieis oriented 180 degrees from the second crimping surface of said seconddie, and said second crimping surface of said first die is oriented 180degrees from said first crimping surface of said second die.
 5. Themethod of claim 1, wherein said plurality of crimped portions on saidtubular portion extend substantially a length of said tubular portionand said tubular portion is crimped directly on said non-metallic core.6. The method of claim 1, wherein said crimping forms a plurality ofcrimped portions oriented 180 degrees apart from an opposing crimpedportion with respect to a longitudinal axis of said non-metallic core.7. The method according to claim 1, wherein said convex surface area ofsaid concave configuration of each of said plurality of crimped portionshave a radius of curvature greater than a radius of curvature of anon-crimped surface formed by said non-crimping area of said firstcrimping die and said second crimping die.
 8. The method according toclaim 1, further comprising abutting contact surfaces of the firstcrimping die and second crimping die to control a travel distance of thecrimping dies when crimping the plurality of crimped portions.
 9. Themethod according to claim 8, wherein an inner diameter of the tubularportion has a tolerance of 0.001 inches and an outer diameter of thetubular portion has a tolerance of 0.002 inches to facilitatecontrolling the travel distance of the crimping dies when crimping theplurality of crimped portions.
 10. The method according to claim 1,further comprising the step of positioning an outer sleeve on thetubular portion, and crimping the outer sleeve to a coupling portion ofthe electrical connector to form a second crimped portion.
 11. Themethod according to claim 10, wherein the outer sleeve has a lengthextending beyond the tubular portion and over the conductor, said methodfurther comprising crimping the outer sleeve to the conductor to form athird crimped portion.
 12. The method according to claim 1, wherein saidtubular portion has un-crimped portions with a convex surface areabetween said crimped portions.
 13. The method according to claim 1,further comprising the step of applying crimping forces to the tubularportion with the concave crimping surfaces of the first crimping die andsecond crimping die at angles of approximately 45 degrees relative to adirection of force applied to said crimping dies.
 14. A method offorming an electrical conductor, comprising: crimping a tubular portiononto a non-metallic core of an electrical conductor to form a firstcrimped portion, a second crimped portion, and a non-crimped portionbetween said first crimped portion and said second crimped portion, thefirst crimped portion and the second crimped portion being formed by adie set including a first crimping die and a second crimping die, eachsaid crimping dies having a crimping area with a first concave crimpingsurface area, a second concave crimping surface area, and a concavenon-crimping surface area between said first crimping surface area andsaid second crimping surface area, the first and second concave crimpingsurface areas having a different radius of curvature than a radius ofcurvature of said concave non-crimping surface, said crimping stepforming said first crimped portion, said second crimped portion, andsaid non-crimped portion to form a crimped tubular portion having asubstantially circular cross section.
 15. The method conductor accordingto claim 14, wherein the radius of curvature of the first concavesurface and the second concave surface area is greater than a radius ofcurvature of the concave non-crimping surface area.
 16. The methodaccording to claim 14, further comprising applying crimping forces tothe tubular portion of the electrical conductor with the first andsecond concave surfaces of the crimping dies at angles of approximately45 degrees relative to a direction of force applied by said crimpingdies.
 17. The method according to claim 14, further comprisingpositioning an outer sleeve on the tubular portion of the electricalconductor and crimping the outer sleeve to a coupling portion of theelectrical connector to form a second crimped portion on said outersleeve.
 18. The method according to claim 17, further comprisingcrimping the outer sleeve to the conductor to form a third crimpedportion.
 19. The method of claim 14, wherein said crimping step formssaid first crimped portion with a convex outer surface, and said secondcrimped portion with a convex outer surface.
 20. The method of claim 19,wherein said convex surface area of said first crimped portion andsecond crimped portion have a radius of curvature greater than theradius of curvature of the non-crimped portion.
 21. The method of claim20, wherein said crimped tubular portion has non-crimped portionsbetween adjacent crimped portions, said non-crimped portions having aconvex surface area.